Electric sound-producer.



M. L. SEVERY.

ELECTRIC SOUND PRODUCER. APPLICATION FILED FEB. 18. 1901.

1,190,332. PdtentedJulyll, 1916. ssusns-sussn.

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' M. L. SEVERY.

ELECTRIC SOUND PRODUCER.

APPLICATION HL-ED FEB. 18. 1907.

1,190,332. Patented July 11, 1916.

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M. L. SEVERY.

ELECTRIC SOUND PRODUCER.

APPLICATION FILED FEB. 18, 1907.

1,190,332. Patented July 11,1916.

5 SHEEfS-SHEET 3.

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M. L. SEVERY.

ELECTRIC SOUND PRODUCER.

APPLICATION HLED FEB. I8. 1901.

1,190,382. Patented July 11, 1916.

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M. L. SEVERY. ELECTRIC SOUND'PRODUCER.

APPLICATION FILED FEB-18,1907.

Patented July 11, 1916.

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' UNITED STATES PATENT OFFICE.

MELVIN L. SEVEBY, OF ARLINGTOiN HEIGHTS, MASSACHUSETTS.

ELECTRIC SOUND-PRODUCER.

To all whom it may concern:

Be it known thatI, MELVIN L. SEVERY, a citizen of the United States, and residing at Arlington Heights, in the county of MiddleseX and Commonwealth of Massachusetts, have invented certain new and useful Improvements in Electric SoundsProducers, of which the following is a full, clear, and exact description. I

This invention relates to, that class of instruments wherein sounds, and particularly musical ones, are produced through the efiect of electric influences upon a sonorous body; andit consists essentially in means whereby a translating device, such as a telephone receiver, may emit musicalsounds through the effect of a variable section of relatively poor conductivity acted upon by a rotating means for varying the amount of current traversing said variable section.

My invention further consists in the construction of practical and eflicient means for applying the foregoing to the production of music in either a key-operated instrument, or an automatic player, and also to telegraphonic or phonographic reproduction.

Referring to the drawings forming part of this specification, Figure. 1 is a diagram illustrating the simplest form in which I have embodied my invention. Fig. 2 shows the invention arranged to be used in connection with a plurality of translating devices. Fig. 2 form drum and forms, the latter broken away to show their differing peripheries. Fig. 3 is an elevation, partly in section, showing the invention provided with means for changing the overtones of the sonorous vibrations communicated to the translating devices. Fig. 4 sets forth another method of changing at will the quality of the sonorous vibrations produced by the instrument. 5 is a detail sectional view showing one of the devices used in this last referred-to construction. Fig. 6 is a side view of one of the stops for throwing into circuit any one or more sets of said devices. Fig. 7 is a cross section of the same. Fig. 8 is a diagram, partly in perspective, showing my arrangement for nullifying the broken effect of an uneven or fractional number of timbrecrests. Fig. 9 shows certain modifications of the timbre-forms and points coacting therewith. Fig. 10 shows other modificationsof the same. Fig. 11 is a face view of a disk provided with rings located upon its Specification of Letters Patent.

is an end elevation of the timbre- Patented July 11,1916.

Application filed February 18, 1907. Serial No. 357,977.

fiat face, which may be disposed as timbreforms. Fig. 12 is a sectional view of the same. Fig. 13 is a diagram of a plurality of translating devices adapted to simultaneously reproduce a variety of tonequalities. Fig. 14 is a sectional view of a construction in which each note has its own'source of power and translating device. Fig. 15 is a sectional view illustrating a preferred mode of mounting, spacing, and insulating the annular timbreforms.

In the construction set forth in Fig. 1, the reference numeral 1 designates a disk of thin sheet metal uniformly rotated with its periphery in proximity to the end of a fixed point or terminal 5; while 6 is a key by means of which to close the circuit between said disk and point and a telephone receiver. The latter consists of the magnet 7. and diaphragm 8. A coil 12 is introduced into this circuit for intensifying the discharge. The periphery of the disk 1 being wavy or radially irregular, the electric discharge between the same and the point or terminal 5 will vary in a corresponding manner; the nearer they are together at any instant, the stronger being such discharge. These variations in current-strength being transmitted to the magnet 7, the diaphragm 8 will be correspondingly. affected; and the speed of the disks rotation being made such as to present a sufiicient number of crests to the point or terminal 5 per second, said diaphragm will emit a musical note, the pitch of which depends on the disks speed, and the quality of which will depend on the shape of the undulations on said periphery." This undulatory peripheral edge of the disk I term a timbre-form; the same being preferably the resultant curve produced by combining with a fundamental the vibrational forms of its overtones, as more particularly described in my companion application, Serial No. 357 9.7 8, now replaced by application Serial No. 756,169. When the disk 1 is revolving in the air or other high resistance gas, it is necessary to introduce an induction coil 12 in the circuit in order to insure the proper dischargeof the current from the disk-edge to the point or terminal 5.. This induction coil is of a well-known type, comprising a primary coil of short thick wire and a secondary coil of long thin wire. A high frequency in the primary circuit, and this interrupter may, be such as isused in wireless telegfor each note of like letter.

one receiver will be used for all the C-notes;

raphy, that is, one which interrupts the primary circuit very rapidly to produce a high tension current in the secondary circuit. This portion of the apparatus is operative if any source of'high tension current is employed, such as is obtained by the use of a Ruhmkorff coil, a static machine, or any other suitable high tension source. The object of an induction coil is to provide a current of sufficient electromotive force to readily leap the air-gap between the point 5 and the disk 1. To further assist the 7 same, a -fine wire 130 may be located beneath the gap between such edge and point, kept heated by current from a source 131 or otherwise, in order to warm the air or gas ther'eat' and increase the conductivity of the latter.

Instead of'a disk, I may use an annulus or washer mounted on a drum 10, as shown in Figs. 2, 3, 5, 14 and 15 as a more commercial form; an entire disk of sheet metal being not only more expensive, but liable to spring laterally.

In Fig. 2 is shown another method of producing a rich musical tone. Here, I grouptogether four disks or timbre forms 1, 1, 1 1 for the production of a single composite note. For instance, the group C has its points or terminals 5 wired to a single key 6 O; the group E'has its points wired to the E key, and so on; the arrangement of each group being as follows: The first, or one of, the timbre forms is peripherally arranged with such a form of curve as acting alone will yield the fundamental of the note desired; another timbre form will give the first harmonic; another, the second har monic, and the fourth,the third harmonic.

All four sets of vibrations being simultaneously communicated to the translating device or telephone, a rich note is the result, and one embracing all the overtones or harmonies ordinarily desired. In the same manner, a largernumber of disks. can be employedin a group, and an increased variety of harmonics given to each note. Another construction shown in the same figure is that by which a separate telephone is employed In other words,

another for all the D-notes, produces a richer efiect than when all the notes are emitted by a single telephone re ceiver. As illustrated the C group of timbre forms are wired to the C key, and the C key has its underlyingcontact wired to the wire 14 which joins, the C-key contact to the 8 C receiver, and so on.

In'Fig. 3 is shown an improved means for rendering the gaps between the timbre forms 1 and their respective points or terminals 5. somewhat better conductors than is done by the warmed air or gas above described. This consists of a liquid, such as water rendered somewhat conductive, withand so on. This in which the rotating timbre forms are located. To do this, the drum 10 is located in a vessel 30, referably cylindrical and vertical, and eitlier formed of a non-conducting material, or having its inner surface nonsure that the rapid rotation of the liquid within the cylinder 30 shall not throw the formerout, the cylinder is closed by a cover 31, and a constant pressure maln'tained by a pipe bringing liquid from a height, or

I otherwise. I

Inasmuch as the rotating timbre forms associated with a single tone are, as shown in the figure, not adapted for easy alteration, I have devised means whereby their relationship to each other can be so changed at Will as to entirely alter the resultanttone quality. By diminishing the loudness of the vibrations produced by one timbre-form of a group, and increasing the loudness of those of a second, while the other two, for

instance, remain equal, the resultant effect is quite different. To enable the operator on this instrument to produce any such different combinations at will throughout all or any section of the notes of the key-board, I join all the fundamental timbre forms,-

the lowest one in each group,to the resistances'16 by Wires 15; all the second timbre forms of each group by wires 15 to the resistances .16; the third, by wires 15 to the resistances 16 and the fourth by wires 15 to the resistances 16. By moving the brushes 17 along said resistances, each set of brushes being preferably shifted equally by the movement of a stop 18 common thereto, the lessened or increased resistance thus put intoor cut out of each circuit, permits practically any desired variations in the strength of the harmonics of all the notes.

The circuit for above described arrangement comprises the current-source 24, wire .25, brush 4, shaft 3, drum 10 or any other conductor joining said shaft to the timbre forms, thence through any of said forms according to the key depressed, across the gaps through the liquid or electrolyte in the cylinder 30 to the nearest terminal point or points 5, through wires 15, 15*, 15 or 15, resistances 16, 16 16 or 16, brushes 17, 17, 17 or 17, wires 19, 19", 19 19, resistances 20, brushes 21, wire 22,'magnet windings 7, and wires 23 back to the current-source 24. By having the wires 19 joined to thewires 19", and the latter joined net is moved closer to the diaphragm 8 and thereby made to more strongly affect the latter and to increase the volume of sound accordingly.

Another, and much more simple method of accomplishing the above described change in timbre of the" instrument, is that illustrated in Figs. 4 to 7. This is based upon the fact discovered by me that the'nearer the points or terminals 5 are to the forms 1, the louder the sound emitted. Hence by varying such distances among the points of a. group, and duplicating these differences throughout the compass of the instrument,

a particular quality is yielded thereby. By

having a plurality of such arrangements, each with its own special timbre, and a stop for throwing it into and out of operation, a wide range of qualities is provided for the instrument. The most practical method of constructing these points 5 consists in stamping those of each group from sheet metal, as shown in Fig. 5, where 50' designates a single member formed with several points or terminals of different lengths. These members 50 can be duplicated in large numbers with but slight expense, and so insure a similarity of quality throughout the entire compass of the instrument. By pro viding the cylinder 30 with several sets of such point-members 50, each set extending throughout a part or the whole of the range of the instrument, but the different sets adapted for unlike qualities, and switching any one or more of such sets into circuit at will, the instrument is given a wide range of timbre. To switch any set of said members 50 in or out, each point-member is furnished with a spring-contact 34: rigidly held at one end and having its opposite end normally out of touch with a contact-bar 35, as shown in Figs. 4, 6 and 7. Beneath these contacts are longitudinally movable rods 36 equal in number to the different sets of members,shown in Fig. 7 as three. On these rods are suitably proportioned wedge-projections 37 so located thereon that, when any rod is drawn lengthwise a specified distance, all the contacts pertaining to a single set of point-members will be raised into touch with the contact-bars 35. Now, a certain rod 36 having been moved and theappropriate spring-contacts 34 put thereby into touch with the bars 35, when the keys 6 are denressed one of the three'qualities of music will be produced. Vhen this rod has been returned and a second rod drawn outward,

a second quality of music will be produced; and so with the third rod. By drawing out two of said rods at the same time, a combination of two qualities is produced when the keys are manipulated; while a movement of all three rods enables a combination of all three qualities to be possible.

It is impossible for the vibrational-crests of a timbre form to meet accurately about its periphery throughout the entire octave of such'forms, where all are rotated upon a common shaft, owing to the fractional nature per unit of time of certain notes. Consequently there will occur a break at certain points in some of the notes. To remedy this, such fractional timbre forms are each provided with two diametrically. opposite points or terminals 5, 5, as shown in Fig. 8, each wired to a separate translating device 7 and provided with means for automatically intensifying the vibrations given through one point to its translating device while diminishing the vibrational strength given to the other translating device through the other point. In accomplishing this, the key 6 for such timbre form is given two brushes 21 21 moving along two separate rheostats 20 20; and a portion of the circuit for each point consists of two annular layers of compressed graphite uniformly rotated. These annular layers of compressed graphite ll, 41 are put into circuit by brushes 47, 47 joined by wires 48, 48 to the brushes 21, 21* respectively. The terminals of the shaft -14 by which said annular resistances are rotated, are insulated one from the other and given brushes 45, 45 joined by wires/i6, 46* to the electromagnets 7, 7*. From each shaft-terminal runs a wire 43, 43 to one of the annular layers, such wires touching the latter at diametrically opposite points. As aresult of this last-described arrangement, when the point of contact of the brush 47 is diametrically opposite to the juncture of the wire 43 with the annular layers 41, the shortest path of the current is through an entire semi-circumference of the same. At the same instant the brush 47 is practically touching the wire 43 and substantially no obstruction is given to the current. Hence, when one translating device is receiving its -maximum of current and so responding its strength. But their combined effect is equal to the maximum of one alone, and so the sound produced remains constant. By timing the rotation of the annular layers of sounding with equal but less than maximum compressed aphite in unison with that of the timbre orm 1, but with the abnormal undulation 2' disposed to reach one of the points or terminals, as 5, simultaneously with the descent of the wire 43 to its farthest from the brush 47, it results that the passage of the break or abnormal undulation occurs when its resonant translation is at its feeblest. Hence such break becomes imperceptible.

I have thus far described the timbre forms as undulatory in'character, but I have discovered that it is possible to produce similar effects with sharp points or abrupt cog teeth, as illustrated in Fig. 9. The undulatory, or graduational eflect'is caused by prolonging peripherally the points or terminals, as 5 or 5. By curving the edge of the point or plate 5 as shown, in Fig. 9, the gradually increasing strength of current passing while a cog 2 is approaching the center point of the said curved edge, and its aduallydiminishing strength as such polnt is passed,

can be arranged to closely approximate if not accurately reproduce all the undulatory character desired. By having said edge somewhat irregular, various overtones can be produced in the resultant music. Instead of employing disks or washershaped members 1, a smooth surfaced cylinder 100 can be used for the same purpose. For instance, the cylinder may be of metal or other conducting material surrounded with an insulating coating cut throughat uniform intervals to expose the conducting surface. Fig. shows such a cylinder having four different kinds of exposed intervals, as diamond shaped spots, undulatory continuous, circular, and laterally elongated.

With the first two, simple lineal points or .termmals 5 may be used; but other forms are preferable for the other two, as the obllque plate 5, or the annular 5.

I'do not restrict myself to a cylindrical rotating member, as the-timbre forms may be located on the flat faces of disks. as 101,

in Figs. 11 and 12, and on the tapes shown in copending application Serial'No. 756,169. enthe annular disks 1 are used, of the type shown in Figs. 2, 3 and 4, it is necessary or at least far better to insulate all but the peripheral edges thereof, in order to.

prevent current-leakage from other parts of the rotating members. A good way in which to do this is by locating a washer 102 of suitable insulating material between each pair of annular disks. This not ,only insulates the, inner surfaces of the annular disks, but accurately positions them upon the cylinder 10, as shown in'Fig.. 15.

In the construction illustrated in Fig.

13, are two translating devices? connected with timbre-members'50 of difierent qual- 1t1es, and provided'with switching rods 36 and plate 35 similar to what set forth'm ymembers extendin being s'pacedforktheproduction of different over- The advantage of this is that there is no diminution in loudness when many notes are sounded simultaneously. i

It should be understood that I may use any desired number of overtones or partials to each note, and that I may use a different number for the same letter of the scalein different parts of the key-board.

What I claim as my invention and for which I desire Letters Patent is as follows, to wit 1. An electric musical instrument comprising a vibrating'body, electrical means and means for producing by the motion 0 v said member pulsations in the current passing through said fluid section between said member and a fixed point of said circuit.

3. An electric musical instrument comprising a vibrating body, electrical means for its vibration, a source .of current, a circuit lncludlng said source and means and having a fluid slightly conductive section,

and a rotatable circular member .extending into said fluid and formed with'an undulaassing a circuit including said source andmeans and having a fluid slightly conductive section, and a plurality of rotatable circular into said fluid and forming a part of t ecircuit; said members ormed with peripheral projections tones of the same musical note.

5. An electric sound producingIinstruinent comprising a vibrating body, electrical means for its vibration, a source of current, a circuit including said source and means and having a fluid slightly conductive section, a plurality of rotatable circular members extending into said fluid and forming a part of the circuit, and means for introducing different resistances into the circuits of said members; said members being formed with peripheral projections spaced for the production of different overtones of the same musical note.

6. An electric musical instrument comprising av vibrating body, electrical means for its vibration, a source of current, a circuit including said source and means andv having a fluid slightly conductive section, a-

plurality of sets of circular members rotated in said fluid, and means for introducing different resistances into the circuits of said members; each set of members being formed with peripheral projections spaced for the production of different overtones of the same musical note.

7. In an electrical sound-producing instrument, the combination of a vibrating body; electrical means for its vibration; a source of electric current; a circuit including said means and source and containing a fluid section; and a movable member located in said fluid section and having an undulating periphery for producing during its movement pulsations in the current flowing through the fluid gap or section between said movable member and a proximate section of the circuit.

8. In an electrical sound-producing instrument, the combination of a vibrating body; electrical means for its vibration; a source of electric current; a circuit including a conductor said means and source, and containing a fluid section; a movable member located in said fluid section, and having an undulating periphery for producing during its movement pulsations in the current passing through said fluid section between said member and a fixed portion of the conductor; and means for varying the conductivity of the fluid medium in the space between said movable member and said fixed portion of the conductor.

9. In an electrical sound-producing instrument, the combination of a vibrating body; electrical means for its vibration; a source of electric current; a circuit including a conductor said means and source, and containing a fluid section; a movable member located in said fluid section, and having an undulating periphery for producing during its movement pulsations in the current passing through said fluid section between said member and a fixed portion of the conductor; and means for heating and thereby varying the conductivity of the fluid medium in the space between said movable member and said fixed portion of the conductor.

10. In an electrical sound-producing instrument, the combination of a vibrating body; electrical means for its vibration; a source of electric current; a circuit including a conductor said means and source, and containing a fluid section; a movable member located in said fluid section, and having an undulating periphery for producing during its movement pulsations in the current passing through said fluid section between said member and a fixed portion of the conductor; and an electric heating device for varying the conductivity of the fluid medium in the space between said movable member and said fixed portion ofthe conductor.

11. In an electrical musical instrument, the combination of a plurality of vibrating bodies; electrical means for their vibration; a source of electric current; branch circuits including said electrical means, and each containing a plurality of conducting terminals and a fluid section; and a plurality of groups of members revoluble in said fluid and each forming a part of one of said circuits, said members having undulatin peripheries spaced from proximate terminals, to produce in the. circuits pulsations of frequencies to educe from the vibrating bodies their respective fundamental tones and selected overtones.

In testimony that I claim the foregoing invention, I have hereunto set my hand this 24th day of December, 1906.

MELVIN L. SEVERY.

Witnesses:

WVILBER E. FARRINGTON, A. B. UPHAM. 

